For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningRemoval Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling
and Enabling.
Disconnect the negative battery cable. Refer to Batter ...
Installation Procedure
Create 5 x 18 mm (4/16 x 11/16 in) slots for MIG-brazing
(1).
Clean and prepare the attaching surfaces for spot welding and brazing.
Note: In MIG-brazing areas 50 mm (2 in) must be kept clear
of structural adhesive.
Apply structural adhesive to all attaching surfaces ...
Compass
The vehicle may have a compass display in the Driver Information Center (DIC).
The compass receives its heading and other information from the Global Positioning
System (GPS) antenna, StabiliTrak, and vehicle speed information.
Avoid covering the GPS antenna, located on the roof, for long perio ...